Biomass is an important primary energy source as well as renewable energy source. As the most promising biomass utilization method, gasification/pyrolysis produces not only useful fuel gases, char and chemicals, but also some byproducts like fly ash, NOx, SO2 and tar. Tar in the product gases will condense at low temperature, and lead to clogged or blockage in fuel lines, filters and engines. Moreover, too much tar in product gases will reduce the utilization efficiency of biomass. Therefore, the reduction or decomposition of tar in biomass derived fuel gases is one of the biggest obstacles in its utilization for power generation. In this paper, we review the literatures pertaining to tar reduction or destruction methods during biomass gasification/pyrolysis. On the basis of their characteristics, the current tar reduction or destruction methods can be broadly divided into five main groups: mechanism methods, self-modification, thermal cracking, catalyst cracking and plasma methods.

The reduction and control technology of tar during biomass gasification/pyrolysis: An overview

Biomass becomes an important primary energy source as well as renewable energy source. As the most promising biomass utilization method, biomass gasification is gaining attention as a route for biomass energy production, but producer gas from this process usually contains unacceptable levels of tar. The tar control and convert is a key issue for a successful application of biomass-derived producer gas. A detail overview on tar chemical and physical properties, reforming mechanism and reaction kinetic model are summarized in this paper.

Tar property, analysis, reforming mechanism and model for biomass gasification—An overview

Biomass gasification is an interesting technology in the future development of a worldwide sustainable energy system, which can help to decrease our current dependence on fossil fuels. Biomass gasification is a thermal process where solid fuel is converted into a useful gas using several gasifying agents such as air, and steam. The producer gas has a great number of applications. The most important is being combustion for power and heat generation as well as raw gas for production of fuels or chemicals. This review mainly presents the recent progresses on tar elimination during the biomass gasification. Then, novel non-catalytic absorption and adsorption methods of tar removal under ambient temperature conducted by our laboratory members were also explained. In our opinion, the tar removal can be conducted by combination of catalytic reforming in the gasifier and oil materials adsorption in the scrubber. Furthermore, the tar catalytic reforming is a most significant step during biomass gasification or pyrolysis. Thus, the development of reasonable catalysts for tar elimination has been faced with a significant challenge in current society.

Recent progresses in catalytic tar elimination during biomass gasification or pyrolysis—A review

Experimental comparison of biomass chars with other catalysts for tar reduction

Chemical looping combustion of solid fuels

This paper presents tar sampling protocols for pressurised and atmospheric large scale gasification processes Methods for constructing sampling lines either to on-line analysers or into sampling systems are described The tar sampling system consists of a heated probe, a particulate filter and a series of impinger bottles Dichloromethane is used as the tar abosrbing solvent The solvent containing bottles are placed in a cold bath so that gradual cooling of the sampled gas from about 0°C to the final temperature −79°C takes place in them Recommendations for suitable sampling gas flow rates and gas temperatures are given Tar characterisation methods based on different garvimetric measurements and GC analysis are described

Steven Deutsch

Papers

Provisional protocol for the sampling and anlaysis of tar and particulates in the gas from large-scale biomass gasifiers. Version 1998 ☆